MAINTAINERS: xen-netback: update my email address

My Citrix email address will expire shortly.
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Acked-by: Wei Liu <wl@xen.org>
Acked-by: Wei Liu <wei.liu@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

MAINTAINERS

@@ -17646,7 +17646,7 @@ F:	Documentation/ABI/testing/sysfs-hypervisor-xen
 
 XEN NETWORK BACKEND DRIVER
 M:	Wei Liu <wei.liu@kernel.org>
-M:	Paul Durrant <paul.durrant@citrix.com>
+M:	Paul Durrant <paul@xen.org>
 L:	xen-devel@lists.xenproject.org (moderated for non-subscribers)
 L:	netdev@vger.kernel.org
 S:	Supported